I've been messing around with various mathematical bits and bobs in QC recently, after stumbling across a nice cache of PC-only HLSL shaders. I've been working on translating some of them to GLSL so they can be used in VDMX, as well as working on a few little projects of my own.
Check them out on my blog (link below), if you get a chance.
alx
http://machinesdontcare.wordpress.com